The present invention relates to cable glands, especially to improvements in cable glands which can be used to surround a portion of a cable in the hole of a partition or another wall that separates two different atmospheres, e.g., a gaseous and a liquid atmosphere, two different liquid atmospheres or a high-pressure atmosphere from a low-pressure atmosphere. Such glands can be used with particular advantage in submersible motor pumps wherein the cable is led out of the motor and is then caused to pass upwardly along the exterior of the pump and of the rising main.
The gland in a submersible motor pump should be sufficiently tight to prevent penetration of liquid into the housing of the electric motor which drives the pump and/or to prevent escape of the fluid from the interior of the motor housing into the surrounding atmosphere, e.g., into a liquid atmosphere well below the sea level. German Utility Model No. 19 13 680 discloses a rather complex cable gland wherein the exterior of a hollow cable is glued to a tubular shell and the exterior of the shell is bonded to a hose which is shrunk thereon. The shell is secured in the hole of a wall between two different atmospheres by a stuffing box. The stranded conductors of the cable are soldered to exposed soldering lugs. Such glands are not ideally suited for use in aggregates wherein a wall must completely separate two different atmospheres. One of the reasons is that any, even slightest, damage to the hollow cable permits leakage of fluid from the higher-pressure area to the lower-pressure area and/or undesirable mixing of the fluids at the opposite sides of the wall. Moreover, the safety which is offered by a stuffing box is rather limited, especially if the difference between the pressures at the opposite sides of the wall is very pronounced. Still further, aging of the material of the stuffing box is likely to result in leakage around the cable. Moreover, pronounced changes in temperature can entail the development of leaks as a result of unequal thermally induced expansion and/or contraction of different parts.